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Oracle® Fusion Middleware Java API Reference for Oracle Coherence 12c (12.1.3.0.0) E47890-01 |
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java.lang.Object
com.tangosol.util.aggregator.TopNAggregator
public class TopNAggregator
TopNAggregator is a ParallelAwareAggregator that aggregates the top N extracted values into an array. The extracted values must not be null, but do not need to be unique.
Nested Class Summary | |
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static class |
TopNAggregator.PartialResult The sorted partial result. |
Nested classes/interfaces inherited from interface com.tangosol.util.InvocableMap.ParallelAwareAggregator |
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InvocableMap.ParallelAwareAggregator.PartialResultAggregator |
Field Summary | |
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protected java.util.Comparator |
m_comparator The Comparator used to order the extracted values. |
protected int |
m_cResults The maximum number of results to include in the aggregation result. |
protected ValueExtractor |
m_extractor The ValueExtractor used by this aggregator. |
protected boolean |
m_fParallel True iff this aggregator is to be used in parallel. |
Constructor Summary | |
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TopNAggregator() Default constructor. |
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TopNAggregator(ValueExtractor extractor, java.util.Comparator comparator, int cResults) Construct a TopNAggregator that will aggregate the top extracted values, as determined by the specified comparator. |
Method Summary | |
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protected void |
addToResult(java.util.Iterator iterValues, TopNAggregator.PartialResult result) Add the specified values to the result if they are within the top-N. |
java.lang.Object |
aggregate(java.util.Set setEntries) Process a set of InvocableMap.Entry objects in order to produce an aggregated result. |
java.lang.Object |
aggregatePartialResults(java.util.Collection colPartialResults) Aggregate the results of the parallel aggregations, producing a partial result logically representing the partial aggregation. |
java.lang.Object |
aggregateResults(java.util.Collection colResults) Aggregate the partial results of the parallel aggregations into a final result. |
protected java.lang.Object[] |
finalizeResult(TopNAggregator.PartialResult result) Finalize the partial aggregation result. |
InvocableMap.EntryAggregator |
getParallelAggregator() Get an aggregator that can take the place of this aggregator in situations in which the InvocableMap can aggregate in parallel. |
void |
readExternal(java.io.DataInput in) Restore the contents of this object by loading the object's state from the passed DataInput object. |
void |
readExternal(PofReader in) Restore the contents of a user type instance by reading its state using the specified PofReader object. |
void |
writeExternal(java.io.DataOutput out) Save the contents of this object by storing the object's state into the passed DataOutput object. |
void |
writeExternal(PofWriter out) Save the contents of a POF user type instance by writing its state using the specified PofWriter object. |
Field Detail |
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protected boolean m_fParallel
protected ValueExtractor m_extractor
protected java.util.Comparator m_comparator
protected int m_cResults
Constructor Detail |
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public TopNAggregator()
public TopNAggregator(ValueExtractor extractor, java.util.Comparator comparator, int cResults)
extractor
- the extractorcomparator
- the comparator for extracted valuescResults
- the maximum number of results to returnMethod Detail |
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public InvocableMap.EntryAggregator getParallelAggregator()
If the returned aggregator is a InvocableMap.ParallelAwareAggregator.PartialResultAggregator
, the partial results of the parallel aggregation may be further aggregated
where optimal.
getParallelAggregator
in interface InvocableMap.ParallelAwareAggregator
public java.lang.Object aggregateResults(java.util.Collection colResults)
aggregateResults
in interface InvocableMap.ParallelAwareAggregator
colResults
- the parallel aggregation resultspublic java.lang.Object aggregate(java.util.Set setEntries)
aggregate
in interface InvocableMap.EntryAggregator
setEntries
- a Set of read-only InvocableMap.Entry objects to aggregatepublic java.lang.Object aggregatePartialResults(java.util.Collection colPartialResults)
aggregated
to produce the final result.aggregatePartialResults
in interface InvocableMap.ParallelAwareAggregator.PartialResultAggregator
colPartialResults
- the partial resultsprotected void addToResult(java.util.Iterator iterValues, TopNAggregator.PartialResult result)
iterValues
- the iterator of values to addresult
- the resultprotected java.lang.Object[] finalizeResult(TopNAggregator.PartialResult result)
result
- the partial resultpublic void readExternal(java.io.DataInput in) throws java.io.IOException
readExternal
in interface ExternalizableLite
in
- the DataInput stream to read data from in order to restore the state of this objectjava.io.IOException
- if an I/O exception occursjava.io.NotActiveException
- if the object is not in its initial state, and therefore cannot be deserialized intopublic void writeExternal(java.io.DataOutput out) throws java.io.IOException
writeExternal
in interface ExternalizableLite
out
- the DataOutput stream to write the state of this object tojava.io.IOException
- if an I/O exception occurspublic void readExternal(PofReader in) throws java.io.IOException
readExternal
in interface PortableObject
in
- the PofReader from which to read the object's statejava.io.IOException
- if an I/O error occurspublic void writeExternal(PofWriter out) throws java.io.IOException
writeExternal
in interface PortableObject
out
- the PofWriter to which to write the object's statejava.io.IOException
- if an I/O error occurs
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Oracle® Fusion Middleware Java API Reference for Oracle Coherence 12c (12.1.3.0.0) E47890-01 |
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